I took clomid (clomiphene) though 5-9 i started my period on the 7th and ovulate the 21 when should i take a pregnancy test?

1 week late: One week after the date you should have started bleeding. If negative, repeat in one week.

3 weeks after sex: Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.